Eadweard Muybridge was a British photographer known for his pioneering work in motion photography. In 1878, he developed a series of photographs that showed a horse in motion, proving that the horse's legs were in the air during galloping. This work laid the foundation for the study of motion and the development of film. Muybridge used tripwires to trigger each camera, creating a sequence of images that showed the horse in motion. This technology helped to challenge the prevailing belief that a horse's legs were in the air when it galloped, and instead showed that the horse's legs were in contact with the ground at all times.